Fix Workflows to take a generic publisher type

Author: soorinpark

Diff for: Samples/WorkflowCombineSampleApp/WorkflowCombineSampleApp/DemoWorker.swift

@@ -17,10 +17,10 @@ extension DemoWorkflow {
         typealias Output = Action
 
         // This publisher publishes the current date on a timer that fires every second
-        func run() -> AnyPublisher<DemoWorkflow.Action, Never> {
+        func run() -> AnyPublisher<Action, Never> {
             Timer.publish(every: 1, on: .main, in: .common)
                 .autoconnect()
-                .map { .init(publishedDate: $0) }
+                .map { Action(publishedDate: $0) }
                 .eraseToAnyPublisher()
         }
 

Diff for: WorkflowCombine/Sources/PublisherWorkflow.swift

@@ -21,21 +21,22 @@
     import Workflow
 
     @available(iOS 13.0, macOS 10.15, *)
+
     extension AnyPublisher: AnyWorkflowConvertible where Failure == Never {
         public func asAnyWorkflow() -> AnyWorkflow<Void, Output> {
             return PublisherWorkflow(publisher: self).asAnyWorkflow()
         }
     }
 
     @available(iOS 13.0, macOS 10.15, *)
-    struct PublisherWorkflow<Value>: Workflow {
-        public typealias Output = Value
+    struct PublisherWorkflow<WorkflowPublisher: Publisher>: Workflow where WorkflowPublisher.Failure == Never {
+        public typealias Output = WorkflowPublisher.Output
         public typealias State = Void
         public typealias Rendering = Void
 
-        let publisher: AnyPublisher<Output, Never>
+        let publisher: WorkflowPublisher
 
-        public init(publisher: AnyPublisher<Output, Never>) {
+        public init(publisher: WorkflowPublisher) {
             self.publisher = publisher
         }
 

Diff for: WorkflowCombine/Sources/Worker.swift

@@ -32,10 +32,11 @@
     public protocol Worker: AnyWorkflowConvertible where Rendering == Void {
         /// The type of output events returned by this worker.
         associatedtype Output
+        associatedtype WorkerPublisher: Publisher where
+            WorkerPublisher.Output == Output, WorkerPublisher.Failure == Never
 
         /// Returns a publisher to execute the work represented by this worker.
-        func run() -> AnyPublisher<Output, Never>
-
+        func run() -> WorkerPublisher
         /// Returns `true` if the other worker should be considered equivalent to `self`. Equivalence should take into
         /// account whatever data is meaningful to the task. For example, a worker that loads a user account from a server
         /// would not be equivalent to another worker with a different user ID.
@@ -85,7 +86,7 @@
                             logger.logFinished(status: "Cancelled")
                         }
                     )
-                    .map { AnyWorkflowAction(sendingOutput: $0) }
+                    .map { AnyWorkflowAction<Self>(sendingOutput: $0) }
             }
             .eraseToAnyPublisher()
             .running(in: context, key: state.uuidString)

Diff for: WorkflowCombine/Tests/Helpers/AnyPublisherTesting.swift

@@ -16,6 +16,7 @@
 
 #if DEBUG
 
+    import Combine
     import Workflow
     import WorkflowTesting
     import XCTest
@@ -35,7 +36,7 @@
             file: StaticString = #file, line: UInt = #line
         ) -> RenderTester<WorkflowType> {
             expectWorkflow(
-                type: PublisherWorkflow<OutputType>.self,
+                type: PublisherWorkflow<AnyPublisher<OutputType, Never>>.self,
                 key: key,
                 producingRendering: (),
                 producingOutput: output,

Diff for: WorkflowCombine/Tests/TestingTests.swift

@@ -183,10 +183,13 @@ private struct TestWorkflow: Workflow {
 }
 
 private struct TestWorker: Worker {
+    typealias Output = String
+    typealias WorkerPublisher = Just<Output>
+
     let input: String
 
-    func run() -> AnyPublisher<String, Never> {
-        Just("").eraseToAnyPublisher()
+    func run() -> WorkerPublisher {
+        Just("")
     }
 
     func isEquivalent(to otherWorker: TestWorker) -> Bool {

Diff for: WorkflowCombine/Tests/WorkerTests.swift

@@ -136,11 +136,14 @@ class WorkerTests: XCTestCase {
         }
 
         struct TestWorker: Worker {
+            typealias Output = WorkerPublisher.Output
+            typealias WorkerPublisher = AnyPublisher<Int, Never>
+
             func isEquivalent(to otherWorker: TestWorker) -> Bool {
                 true
             }
 
-            func run() -> AnyPublisher<Int, Never> {
+            func run() -> WorkerPublisher {
                 [1, 2].publisher
                     .delay(for: .milliseconds(1), scheduler: RunLoop.main)
                     .eraseToAnyPublisher()